safe clearance

• 安全距离,安全余量,安全间隙,安全净空

safe clearance的用法和样例：

例句

1. The minimum vertical clearance through the tunnel is 3m.
   这个隧道的最小垂直净空是三米。
2. Research in Motion has received clearance to sell its BlackBerry device in China after eight years of trying.
   在运动中的研究已经收到净空尝试在八年之后在中国卖它的黑莓装置。